p. 264
तथापि वेदेन विदन्ति वेदं ये ब्राह्मणा वेदविदो भवन्ति ॥ ४३ ॥
In plain words
Even so: it is by the Veda that the Veda is known. The brāhmaṇas who know it that way are the ones who know the Veda.
Close to the Sanskrit
Even so, by the Veda they know the Veda; those brāhmaṇas who do so become knowers of the Veda.